Ah, that makes a lot more sense, yes! Thank you.

I'm in love with the 18F4550 (or 2550) because of the USB, so I'm stuck with 5v. But I can use a TI 78ST105 switching regulator instead of the LM7805 which will bring my effeciency from 12v to v5 to > 85%.

I've used the 4550 for a couple other projects so I'm familair with it. As far as power consumption I plan on using a USB sense from the 5V USB power to turn off the USB when not connected to save power, thus not affecting my ability to write to the EEPROM on shutdown. The USB will be used mainly for setup and to retrieve data, but will be disconnected 99.99% of the time.

New Schematic: